virtio: Fix used_idx wrap-around
authorAnthony Liguori <aliguori@us.ibm.com>
Wed, 7 Nov 2007 21:49:24 +0000 (15:49 -0600)
committerRusty Russell <rusty@rustcorp.com.au>
Mon, 12 Nov 2007 02:59:09 +0000 (13:59 +1100)
commit1bc4953ed44454c7f53d0b609445d1534981ee75
tree05f67206d6978261ad2569d3a0030f0299331191
parent4d125de3a5d130054df2285e542c1491d214d3e8
virtio: Fix used_idx wrap-around

The more_used() function compares the vq->vring.used->idx with last_used_idx.
Since vq->vring.used->idx is a 16-bit integer, and last_used_idx is an
unsigned int, this results in unpredictable behavior when vq->vring.used->idx
wraps around.

This patch corrects this by changing last_used_idx to the correct type.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
drivers/virtio/virtio_ring.c